The two‐day wave in EOS MLS temperature and wind measurements during 2004–2005 winter

Limpasuvan, Varavut; Wu, Dong L.; Schwartz, M.; Waters, J. W.; Wu, Qian; Killeen, T. L.

doi:10.1029/2005gl023396

Cited by 57 publications

(63 citation statements)

References 18 publications

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“…In both cases, a reversal of the mean zonal flow direction is measured between 50-55 • N, accompanied by a steep increase of the temperature in the Arctic (blue dashed line). The temperature data are daily and zonally averaged AURA/MLS observations Limpasuvan et al, 2005) between 60-80 • N. The wind and temperature observations are consistent with the analysis of meteorological data in the Arctic of various winters (Labitzke and Kunze, 2009;Manney et al, 2009;Dörnbrack et al, 2012). In the beginning of January, when the vortex had the strongest intensity, the mean eastward zonal-winds strongly increased to 60-80 m s −1 .…”

Section: The Sudden Stratospheric Warming Eventssupporting

confidence: 50%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

et al. 2013

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Abstract. Although the links between stratospheric dynamics, climate and weather have been demonstrated, direct observations of stratospheric winds are lacking, in particular at altitudes above 30 km. We report observations of winds between 8 and 0.01 hPa (~35–80 km) from October 2009 to April 2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station. The altitude range covers the region between 35–60 km where previous space-borne wind instruments show a lack of sensitivity. Both zonal and meridional wind components were obtained, though not simultaneously, in the latitude range from 30° S to 55° N and with a single profile precision of 7–9 m s–1 between 8 and 0.6 hPa and better than 20 m s–1 at altitudes above. The vertical resolution is 5–7 km except in the upper part of the retrieval range (10 km at 0.01 hPa). In the region between 1–0.05 hPa, an absolute value of the mean difference < 2 m s–1 is found between SMILES profiles retrieved from different spectroscopic lines and instrumental settings. Good agreement (absolute value of the mean difference of ~2 m s–1) is also found with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis in most of the stratosphere except for the zonal winds over the equator (difference > 5 m s−1). In the mesosphere, SMILES and ECMWF zonal winds exhibit large differences (> 20 m s–1), especially in the tropics. We illustrate our results by showing daily and monthly zonal wind variations, namely the semi-annual oscillation in the tropics and reversals of the flow direction between 50–55° N during sudden stratospheric warmings. The daily comparison with ECMWF winds reveals that in the beginning of February, a significantly stronger zonal westward flow is measured in the tropics at 2 hPa compared to the flow computed in the analysis (difference of ~20 m s–1). The results show that the comparison between SMILES and ECMWF winds is not only relevant for the quality assessment of the new SMILES winds, but it also provides insights on the quality of the ECMWF winds themselves. Although the instrument was not specifically designed for measuring winds, the results demonstrate that space-borne sub-mm wave radiometers have the potential to provide good quality data for improving the stratospheric winds in atmospheric models.

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Section: The Sudden Stratospheric Warming Eventssupporting

confidence: 50%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

et al. 2013

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“…Amplitudes of QTDWs in temperature and wind can reach 12 K (Tunbridge et al, 2011) and 60 m s −1 (Wu et al, 1993). Traces of QTDWs can also be found in atmospheric H 2 O, carbon monoxide, OH emission, and height of the F2 layer (Wu et al, 1993;Randel, 1994;Forbes and Zhang, 1997;Limpasuvan and Wu, 2003;Limpasuvan et al, 2005;Tunbridge et al, 2011;Pedatella and Forbes, 2012). Moreover, QTDWs are found to be important in photochemical processes in the mesopause region (Kulikov, 2007).…”

Section: Introductionmentioning

confidence: 97%

Global climatological variability of quasi-two-day waves revealed by TIMED/SABER observations

et al. 2013

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This paper presents characteristics of quasi-two-day waves (QTDWs) in the mesosphere and lower thermosphere (MLT) between 52° S and 52° N from 2002 to 2011 using TIMED/SABER temperature data. Spectral analysis suggests that dominant QTDW components at mid-high latitudes of the Southern Hemisphere (SH) and the Northern Hemisphere (NH) are (2.13, W3) and (2.04, W4), respectively. The most remarkable QTDW is (2.13, W3), which happened in the southern summer of 2002–2003 at 32° S from 60 to 90 km in altitude. Its downward phase propagation indicates upward propagation of the wave energy and a potential source region below 60 km. Analysis of horizontal wind fields in the same period shows the westward and southward propagation of (2.13, W3) and a possible reflection region above 90 km. Fundamental parameters of QTDWs present significant interhemispheric differences and interannual variations in statistical analysis. Amplitudes in the SH are twice larger than that in the NH, and vertical wavelengths are a little longer in the SH. QTDWs may endure stronger dissipation in southern summer because of shorter durations of their attenuation stages. Impact of the equatorial quasi-biennial-oscillation (QBO) on QTDWs can extend to mid-high latitudes of both hemispheres. It seems easier for QTDWs to propagate upward in the equatorial QBO's westerly phase in the lower stratosphere and easterly phase in the middle stratosphere. Interannual variations of QTDW strength may be influenced by solar activity as well. Strengths of QTDWs appear to be stronger (weaker) in the solar maximum (minimum)

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“…This method has been used by a number of other studies (e.g., Limpasuvan et al, 2005;Baumgaertner et al, 2008;Limpasuvan and Wu, 2009;McDonald et al, 2011;Day et al, 2011). The uncertainty in the wave amplitude estimated using this method is usually ± 0.6 K or smaller, e.g., Day et al (2011).…”

Section: Atmosmentioning

confidence: 99%

Mean winds, temperatures and the 16- and 5-day planetary waves in the mesosphere and lower thermosphere over Bear Lake Observatory (42° N, 111° W)

2012

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Abstract. Atmospheric temperatures and winds in the mesosphere and lower thermosphere have been measured simultaneously using the Aura satellite and a meteor radar at Bear Lake Observatory (42 • N, 111 • W), respectively. The data presented in this study is from the interval March 2008 to July 2011.The mean winds observed in the summer-time over Bear Lake Observatory show the meridional winds to be equatorward at meteor heights during April-August and to reach monthly-mean velocities of −12 m s −1 . The mean winds are closely related to temperatures in this region of the atmosphere and in the summer the coldest mesospheric temperatures occur about the same time as the strongest equatorward meridional winds. The zonal winds are eastward through most of the year and in the summer strong eastward zonal wind shears of up to ∼4.5 m s −1 km −1 are present. However, westward winds are observed at the upper heights in winter and sometimes during the equinoxes. Considerable inter-annual variability is observed in the mean winds and temperatures.Comparisons of the observed winds with URAP and HWM-07 reveal some large differences. Our radar zonal wind observations are generally more eastward than predicted by the URAP model zonal winds. Considering the radar meridional winds, in comparison to HWM-07 our observations reveal equatorward flow at all meteor heights in the summer whereas HWM-07 suggests that only weakly equatorward, or even poleward flows occur at the lower heights. However, the zonal winds observed by the radar and modelled by HWM-07 are generally similar in structure and strength.Signatures of the 16-and 5-day planetary waves are clearly evident in both the radar-wind data and Aura-temperature data. Short-lived wave events can reach large amplitudes of up to ∼15 m s −1 and 8 K and 20 m s −1 and 10 K for the 16-and 5-day waves, respectively. A clear seasonal and shortterm variability are observed in the 16-and 5-day planetary wave amplitudes. The 16-day wave reaches largest amplitude in winter and is also present in summer, but with smaller amplitudes. The 5-day wave reaches largest amplitude in winter and in late summer. An inter-annual variability in the amplitude of the planetary waves is evident in the four years of observations. Some 41 episodes of large-amplitude wave occurrence are identified. Temperature and wind amplitudes for these episodes, A T and A W , that passed the Student T-test were found to be related by, A T = 0.34 A W and A T = 0.62 A W for the 16-and 5-day wave, respectively.

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The two‐day wave in EOS MLS temperature and wind measurements during 2004–2005 winter

Cited by 57 publications

References 18 publications

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Global climatological variability of quasi-two-day waves revealed by TIMED/SABER observations

Mean winds, temperatures and the 16- and 5-day planetary waves in the mesosphere and lower thermosphere over Bear Lake Observatory (42° N, 111° W)

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